Project Summary The overall goal of the proposed work is to develop a platform capable of delivering and monitoring adherence, proficiency, and safety of a home-based simplified Tai Chi intervention for older adults. During Phase I of this Fast-Track STTR project we will further develop a novel approach to assessing Tai Chi performance adherence, proficiency, and safety based on wearable sensor data. Metrics of adherence and safety will be determined. A multi-item proficiency scoring metric will be developed using a modified Delphi consensus process. Subjects will be asked to perform movements in the laboratory from the simplified Tai Chi intervention while wearing a network of nine-axis sensors. Proficiency will be assessed by Tai Chi experts using the previously developed metric. Collected data will be used to aid development of algorithms to predict adherence, proficiency, and safety. Sensitivity analyses will be performed to identify the minimum number of sensors necessary to achieve satisfactory results. During Phase I we will also carry out stakeholder focus groups to inform the development of a user-friendly Tele-Tai Chi platform. During Phase II of this Fast-Track STTR project we will develop a user-friendly ?Tele-Tai Chi? platform via a user-centered design approach. To accomplish this aim, we will develop a platform consisting of a wireless body sensor network, a tablet computer (to collect data, and provide instructions and feedback), and a web- based dashboard (for remote access to program data). An iterative design approach will be employed based on the needs of the end-user including practitioners, Tai Chi instructors, and researchers. Focus groups will be employed to ascertain this information over the course of the project. Next we will demonstrate feasibility of tracking adherence, proficiency and safety over a 3-month training period in a 3 consecutive cohorts (n=10 each) of older adults. For this preliminary test of our platform, subjects will participate in a 12-week home-based simplified Tai Chi program delivered via pre-programed tablets, supplemented with laboratory visits at baseline, 3, 6, and 12 weeks. Subjects will be asked to practice at home for 45 minutes a minimum of 3 times per week. Instumented laboratory visits will: a) simulate typical home practice sessions and provide additonal data on usability and inform estimates of adherence and proficiency algorithms; and b) allow for longitudinal evaluation of function and postural control, which will be used to explore associations between platform-derived measures of adherence and proficiency and fall risk.